1. Field of the Invention
The present invention relates to an animal litter box for animals kept in rooms such as cats and dogs, which can be cleaned easily and can reduce an amount of animal litter to be discarded as waste.
2. Description of Related Art
A plastic container in which granular materials called animal litter are contained has been used as an animal litter box for animals kept in rooms such as cats and dogs. Mineral materials such as zeolite, river sand and bentonite which becomes hard when it absorbs liquid like urine, and cellulose grains made of crushed pulp hardened to shape granular. An animal such as a cat enters the animal litter box, and evacuates urine or feces on the animal litter. An owner removes the animal litter soiled with urine or feces with a scoop along with feces out of a container, and replenishes new animal litter in accordance with an amount of the animal litter removed.
However, since pet animals like cats have the habit of mixing animal litter with their paws after evacuation, an amount of animal litter soiled with urine or feces is increased and the soiled animal litter is scattered. Thus, it is difficult to remove only the soiled animal litter. Furthermore, the zeolite and river sand do not absorb urine, and bentonite and cellulose grains absorb urine to some extent but cannot absorb it completely. On this account, urine passes through the litter and tends to be held in the container. Therefore, the owner needs not only discard a part of the animal litter at every time of animal evacuation but also needs to change all of the animal litter contained in the container once a week or two weeks, to clean and dry the container, and to place new litter in the container for keeping the animal litter box cleaned. It increases an amount of animal litter to be discarded. Moreover, when mineral sand such as zeolite is used as the animal litter, it is difficult to be discarded as waste, because it is non-combustible.
As a product to solve the problems mentioned above, an animal litter box disclosed in Japanese unexamined patent publication No. 10-229768-A (Patent Document 1) is developed, for example. In the animal litter box disclosed in patent Document 1, a plurality of water repellent granular materials are placed in a container having a bottom part comprising a sheet with liquid passing structure. A liquid-absorbing sheet supported by a support body is disposed under the bottom part of the container in close contact with the sheet, in which urine passes through the water repellent granular materials and through the bottom part of the container, and then is absorbed into the liquid-absorbing sheet. Accordingly, since urine does not remain in the container, the animal litter box is cleaned only by changing the liquid-absorbing sheet once a day. It is fine that the entire granular materials are changed once a month or two months. The animal litter box ca save the trouble to change the animal litter and can reduce an amount of waste.
However, the liquid-absorbing sheet supported by the support body is disposed under the bottom of the container in contact with the bottom in this traditional example. Thus, when an amount of urine absorbed into the liquid-absorbing sheet is increased by long time use, urine returns back to the granular materials to soil the entire granular materials. Moreover, the liquid-absorbing sheet should be changed once a day, waste is generated everyday even though it occurs once a day, being troublesome.